MD, PhD. Molecular Biologist, Department of Pathology, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro (RJ), Brazil.
MD, PhD. Molecular Biologist, Department of Pathology, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro (RJ), Brazil.
Sao Paulo Med J. 2024 May 10;142(5):e2023140. doi: 10.1590/1516-3180.2023.0140.R1.04032024. eCollection 2024.
The human telomerase reverse transcriptase (hTERT) enzyme, encoded by the hTERT gene, synthesizes protective telomeric sequences on chromosomes and plays a fundamental role in cancer formation. Methylation of the hTERT gene has an upregulatory effect, increasing hTERT enzyme synthesis and allowing continuous tumor cell division.
In a group of patients with breast cancer, we aimed to analyze the methylation status of hTERT in the tumor, surrounding tissue, and circulating free deoxyribonucleic acid (cfDNA) of blood collected on the day of mastectomy and then approximately one year later.
A prospective study was conducted at a university hospital in Rio de Janeiro, Brazil.
Samples were collected from 15 women with breast cancer on the day of mastectomy and approximately one year postoperatively. cfDNA was analyzed by sodium bisulfite conversion, followed by polymerase chain reaction, electrophoresis, and silver nitrate staining.
Methylation of hTERT was detected in the tumors and surrounding tissues of all 15 patients. Five patients displayed hTERT methylation in the cfDNA from the blood of the first collection. Of the ten patients who returned for the second collection, three showed methylation. Two patients with methylation in the first collection did not display methylation in the second collection. One patient with no methylation in the first collection displayed methylation in the second collection, and one patient had a diminished level of methylation in the second collection.
Only one-third of patients displayed methylation in their cfDNA, which may be related to the success of chemotherapy.
人类端粒酶逆转录酶（hTERT）酶由 hTERT 基因编码，在染色体上合成保护性端粒序列，在肿瘤形成中起着至关重要的作用。hTERT 基因的甲基化具有上调作用，增加 hTERT 酶的合成，使肿瘤细胞能够持续分裂。
在一组乳腺癌患者中，我们旨在分析肿瘤、周围组织以及在乳腺癌根治术当天和大约一年后采集的血液中循环游离脱氧核糖核酸（cfDNA）中 hTERT 的甲基化状态。
这是在巴西里约热内卢的一所大学医院进行的一项前瞻性研究。
在乳腺癌根治术当天和大约一年后，从 15 名女性乳腺癌患者中采集样本。cfDNA 通过亚硫酸氢钠转化进行分析，然后进行聚合酶链反应、电泳和硝酸银染色。
15 名患者的肿瘤和周围组织中均检测到 hTERT 甲基化。在第一次采集的血液 cfDNA 中，有 5 名患者显示 hTERT 甲基化。在 10 名返回进行第二次采集的患者中，有 3 名患者显示甲基化。在第一次采集时显示甲基化的 2 名患者在第二次采集时未显示甲基化。在第一次采集时无甲基化的 1 名患者在第二次采集时显示甲基化，1 名患者的甲基化水平在第二次采集时降低。
只有三分之一的患者的 cfDNA 显示甲基化，这可能与化疗的成功有关。
